Thermosetting bis-citraconimide resin composition

Abstract

Provided is a thermosetting bis-citraconimide resin composition which has a viscosity suitable for handling and is capable of obtaining a cured product having both dielectric properties (low relative permittivity and low dielectric loss tangent) and heat resistance. The thermosetting bis-citraconomide resin composition comprises (A) a bis-citraconomide compound, (B) a mono-citraconomide compound having a melting point of 60 DEG C or less, (C) an epoxy resin, and (D) an epoxy resin curing agent, and (E) a curing accelerator.

Description

Technical Field

[0001] This invention relates to thermosetting bis(citric acid)imide resin compositions. Background Technology

[0002] In mobile communication equipment, network infrastructure equipment, mainframe computers, and other electronic devices, the speed and capacity of signals used are increasing year by year. Furthermore, in the fields of ITS (In-line Systems) and indoor short-range communications, the practical application and implementation plans for new systems that handle high-frequency wireless signals are also progressing. Consequently, the printed circuit boards mounted on these electronic devices require high-frequency support in the 20GHz range. Therefore, even in the underfill material, dielectric properties such as low relative permittivity and low dielectric loss tangent are required to reduce transmission loss.

[0003] Materials with low relative permittivity and low dielectric loss tangent include thermosetting resins such as modified polyphenylene ether resins and maleimide resins, as well as thermoplastic resins such as fluoropolymers, styrene resins, and liquid crystal polymers. However, these resins have high melt viscosity, resulting in hard and brittle cured products. In contrast, citrileimide resin has a low melt viscosity compared to the aforementioned resins, yielding cured products with excellent dielectric properties and heat resistance (Patent Document 1, Patent Document 2). However, compared to liquid epoxy resin, citrileimide resin has a high viscosity at room temperature, posing some challenges in operability. Existing technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2023-018240 Patent document 2: Japanese Patent Application Publication No. 2022-147022. Summary of the Invention The problem the invention aims to solve

[0005] Therefore, the object of the present invention is to provide a thermosetting bis-citronoisimide resin composition having a viscosity suitable for operation and being able to obtain a cured product that combines dielectric properties (low relative permittivity and low dielectric loss tangent) and heat resistance. Problem Solving Methods

[0006] In order to solve the above-mentioned problems, the inventors conducted repeated and in-depth research and discovered that the following thermosetting bis(citroxy)imide resin composition can achieve the above-mentioned objectives, thus completing the present invention. That is, the present invention is to provide the following thermosetting bis(citroxy)imide resin composition. [1] A thermosetting bis(citroxy)imide resin composition comprising: (A) A citrile imide compound represented by the following formula (1), [Chemical Formula 1] (In formula (1), B is a divalent organic group.) (B) Monocitracinimide compounds with a melting point below 60°C, represented by the following formula (2), [Chemical Formula 2] (In formula (2), A is a group selected from hydrocarbon groups shown in the following structures.) [Chemical Formula 3] (R is an independent hydrogen atom or a monovalent hydrocarbon group with 1 to 10 carbon atoms) Q is a straight-chain or branched alkylene group with 1 to 10 carbon atoms; * indicates bonding with the nitrogen atom in the citrileimide group. (C) Epoxy resin, (D) Epoxy resin curing agent, and (E) Curing accelerator. [2] According to the thermosetting bis(citric acid)imide resin composition described in [1], wherein, In formula (1), B is at least one group selected from groups represented by the following structures and hydrocarbon groups from a dimer acid backbone. [Chemical Formula 4] (* refers to the bond with the nitrogen atom in the citrile imide group, where n is 1 to 20.) [3] According to the thermosetting bis(citronellal)imide resin composition described in [1] or [2], wherein, (A) The melting point of the bis-citronimidide compound is below 25°C. [4] The thermosetting bis-citronimid resin composition according to any one of [1] to [3], wherein, (A) The number average molecular weight of the bis-citronimidide compound is 200 to 10,000. [5] The thermosetting bis-citronellimide resin composition according to any one of [1] to [4], wherein, (C) Epoxy resin is an epoxy resin having two or more epoxy groups in one molecule. [6] The thermosetting bis-citronimid resin composition according to any one of [1] to [5], wherein, (D) The epoxy resin curing agent is selected from one or more of amine compounds, phenolic compounds, acid anhydride compounds and reactive ester compounds. [7] The thermosetting bis-citronellimide resin composition according to any one of [1] to [6], wherein, (E) The curing accelerator is selected from one or more of imidazole-based curing accelerators, organophosphorus-based curing accelerators and tertiary amine-based curing accelerators. [8] The thermosetting bis-citronellimide resin composition according to any one of [1] to [7], wherein, Relative to 100 parts by mass of components (A) and (B), (B) The composition is 1 to 30 parts by weight. (C) The composition is 1 to 100 parts by weight. The molar equivalent ratio of functional groups reacting with epoxy groups in component (D) to 1 molar equivalent of epoxy groups in component (C) is 0.1–4.0. (E) Components are 0.01 to 20 parts by mass. The effects of the invention

[0008] The thermosetting bis-citronimid resin composition of the present invention has a viscosity suitable for operation and can produce cured products that combine dielectric properties (low relative permittivity and low dielectric loss tangent) and heat resistance. Detailed Implementation

[0009] The present invention will now be described in detail.

[0010] [(A) Bisciconimidin compound] The component (A) used in this invention is a bis-citronimidide compound represented by the following formula (1), and is the main component of the curable bis-citronimidide resin composition of this invention. The citronimidide group is a group in which one hydrogen atom of the maleimide group is replaced by a methyl group. The bis-citronimidide compound of component (A), through the effect of the methyl group of the citronimidide group, not only exhibits a lower dielectric constant and a lower dielectric loss tangent, but also a lower melting point, and its compatibility with other components is improved compared with maleimide compounds of the same skeleton. [Chemical Formula 5] (In formula (1), B is a divalent organic group.) If it is such a bis-citronimidide compound, it is easy to prepare amine compounds as raw materials, has excellent solubility in solvents, and is easy to synthesize, so it is preferred.

[0011] There are no particular limitations on the properties and number-average molecular weight of the bis-citconimide compound of component (A) at room temperature, but it is preferred to be in a liquid state at 25°C. Furthermore, the number-average molecular weight of the bis-citconimide compound of component (A) is preferably 200–10000, more preferably 200–5000, and even more preferably 200–2000. In this specification, the number-average molecular weight is determined under the following conditions. 1 The number-average molecular weight calculated from the H-NMR determination results. [Measurement Conditions] Device: AVANCE III400 manufactured by Burker Solvent: CDCl3 Internal standard: Tetramethylsilane (TMS)

[0012] In addition, in order to obtain low elasticity and excellent dielectric properties after curing (low relative permittivity and low dielectric loss tangent), the divalent organic group represented by B in the bisciconimide compound is more preferably a group selected from at least one of the groups represented by the following structure and hydrocarbon groups from the dimer acid skeleton.

[0013] [Chemical Formula 6] (* indicates bonding with the nitrogen atom in the citrate imide group. n ranges from 1 to 20.)

[0014] The dimer acids referred to here are liquid dicarboxylic acids with 36 carbon atoms, formed by the dimerization of 18-carbon unsaturated fatty acids from natural sources such as plant oils, and produced primarily from these dicarboxylic acids. The dimer acid skeleton is not a single skeleton but has multiple structures and exists in various isomers. Representative dimer acids are classified by names such as linear (a), monocyclic (b), aromatic cyclic (c), and polycyclic (d). In this specification, the dimer acid backbone refers to the group derived from a dimer diamine having a structure obtained by replacing the carboxyl group of such a dimer acid with a primary aminomethyl group. That is, the hydrocarbon group derived from the dimer acid skeleton of the bisciconimide compound, which is component (A), is preferably a branched divalent hydrocarbon group in each dimer acid represented by (a) to (d) below, in which two carboxyl groups are replaced by methylene groups. Furthermore, in the case where the bisciconimide compound of component (A) has a hydrocarbon group derived from the dimer acid skeleton, from the viewpoint of the heat resistance and reliability of the cured product, the hydrocarbon group derived from the dimer acid skeleton is more preferably a hydrocarbon group having a structure in which the carbon-carbon double bond in the hydrocarbon group derived from the dimer acid skeleton is reduced by hydrogenation reaction.

[0015] [Chemical Formula 7]

[0016] (A) The bis-citronimidide compound can be used alone or in combination with two or more compounds.

[0017] In the thermosetting bis-citronimidimide resin composition of the present invention, the proportion of component (A) relative to the whole composition is preferably 50-90% by mass, more preferably 60-85% by mass, and even more preferably 70-80% by mass.

[0018] [(B) Monociconimidin compound] The monociconimidin compound that is component (B) of the present invention is shown in the following formula (2). [Chemical Formula 8] (In formula (2), A is a group selected from hydrocarbon groups shown in the following structures.)

[0019] [Chemical Formula 9] In the above formula, R is an independent hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of monovalent hydrocarbon groups include alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, and aralkyl groups having 7 to 10 carbon atoms. Preferably, it is a hydrogen atom or a methyl group. In the above formula, Q is an alkylene group having 1 to 10 carbon atoms, which can be either linear or branched. Preferably, it is methylene, ethylene, etc. If the compound is a monociconimidin, the amine compound used as a raw material is easy to prepare, has excellent solubility in solvents, and is easy to synthesize, thus it is preferred. Additionally, in the above formula, * refers to the bond with the nitrogen atom in the citrile imide group.

[0020] The monociconimidin compound in component (B) can be used as a reactive diluent. From the viewpoint of reducing viscosity, component (B) is a substance with a melting point below 60°C, preferably a substance with a melting point below 25°C. Even if the monociconimidin compound is solid at room temperature (25°C), as long as its melting point is below 60°C, when it is incorporated into the composition by heating and mixing, it becomes liquid in the composition even at 25°C due to the decrease in freezing point, thereby achieving the effect of reducing viscosity. In this invention, by using monociconimide compounds as reactive diluents, not only can the viscosity be reduced, but also a cured product with dielectric properties (low relative permittivity and low dielectric loss tangent) and heat resistance can be obtained.

[0021] The amount of component (B) is preferably 1 to 30 parts by mass of the total 100 parts by mass of components (A) and (B), more preferably 10 to 20 parts by mass.

[0022] [(C) Epoxy Resin] (C) epoxy resin is added to promote the reaction between (A) bis-citconimide compound and (B) mono-citconimide compound.

[0023] The epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule, but conventionally known epoxy resins may also be used. Examples include bisphenol-type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; phenolic varnish-type epoxy resins such as phenol, cresol, bisphenol A, and bisphenol F; alicyclic epoxy resins such as dicyclopentadiene type epoxy resin and 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylic acid ester; and epoxy resins produced by reacting amine compounds such as diaminodiphenylmethane, isocyanuric acid, and aminophenol with the surface... Glycidylamine type epoxy resin obtained by the reaction of chlorohydrins; polyfunctional phenolic epoxy resins such as resorcinol type epoxy resin and resorcinol phenolic varnish type epoxy resin; stilbene type epoxy resin, epoxy resin containing a triazine skeleton, epoxy resin containing a fluorene skeleton, triphenol alkane type epoxy resin, biphenyl type epoxy resin, xylene-type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, and anthracene and other polycyclic aromatic diglycidyl ether compounds, as well as phosphorus-containing epoxy resins in which phosphorus compounds are introduced. Among these, bisphenol A type epoxy resin, dicyclopentadiene type epoxy resin, glycidylamine type epoxy resin, biphenyl aralkyl type epoxy resin, and naphthalene type epoxy resin are preferred. They can be used individually or in combination with two or more.

[0024] When the total mass of components (A) and (B) is set to 100 parts by mass, the mass of component (C) is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, and particularly preferably 10 to 30 parts by mass. If the amount of epoxy resin (C) is within this range, a cured product with low dielectric properties (low dielectric constant and low dielectric loss tangent) can be obtained.

[0025] (D) Epoxy Resin Curing Agent (D) The epoxy resin curing agent is added to react with the epoxy groups contained in (C) epoxy resin. The epoxy resin curing agent only needs to have a functional group that reacts with the epoxy groups, and is preferably selected from at least one of amine compounds, phenolic compounds, acid anhydride compounds, and reactive ester compounds. From the viewpoint of the dielectric properties of the composition, a phenolic compound is more preferred.

[0026] The amine compound can be any commonly known compound. From the viewpoint of processability and moisture resistance reliability, aromatic amine compounds are preferred. Preferred examples include, for instance, aromatic diaminodiphenylmethane compounds such as 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, and 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane; 2,4-diaminotoluene; 1,4-diaminobenzene; 1,3-diaminobenzene, etc., and more preferably, aromatic diaminodiphenylmethane compounds such as 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, and 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane. They can be used alone or in combination of two or more.

[0027] The aforementioned amine compounds can be either liquid or solid at room temperature (20–30°C). Liquid amine compounds can be directly mixed, but for solid amine compounds, direct mixing will lead to an increase in the viscosity of the resin composition and a significant deterioration in workability. Therefore, it is preferable to pre-melt mix them with the aforementioned epoxy resin, preferably at the specific mixing ratio described later, within a temperature range of 70–150°C for 1–2 hours. If the mixing temperature is below 70°C, the amine compounds may not be sufficiently compatible; if the mixing temperature exceeds 150°C, the amine compounds may react with the epoxy resin, leading to an increase in viscosity. Furthermore, if the mixing time is less than 1 hour, the amine compounds may not be sufficiently compatible, potentially leading to an increase in viscosity; if the mixing time exceeds 2 hours, the amine compounds may react with the epoxy resin, resulting in an increase in viscosity.

[0028] Phenolic compounds can be any commonly known compounds. Examples include phenolic varnish resins, phenolic resins containing a naphthalene ring, aralkyl-type phenolic resins, triphenol alkane-type phenolic resins, aralkyl-type phenolic resins containing a biphenyl skeleton, biphenyl-type phenolic resins, alicyclic phenolic resins, heterocyclic phenolic resins, phenolic resins containing a naphthalene ring, resorcinol-type phenolic resins, phenolic varnish-type allyl phenolic resins, bisphenol A type resins, and bisphenol F type resins. These can be used alone or in combination of two or more.

[0029] Anhydride compounds can be commonly known compounds. Examples include, for instance, 4-methylcyclohexane-1,2-dicarboxylic anhydride, 3,4-dimethyl-6-(2-methyl-1-propenyl)-1,2,3,6-tetrahydrophthalic anhydride, 1-isopropyl-4-methyl-bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylnadic anhydride, pyromellitic dianhydride, maleic basilene, benzophenone tetracarboxylic anhydride, 3,3',4,4'-biphenyltetrabisbenzophenone tetracarboxylic anhydride, (3,4-dicarboxyphenyl) ether dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, etc. They can be used individually or in combination with two or more.

[0030] The active ester compounds can be commonly known compounds. Examples include, for instance, active ester compounds containing a dicyclopentadiene-type phenolic resin structure, active ester compounds containing a phenolic varnish structure, active ester compounds containing a naphthyl ring structure, active ester compounds containing an aralkyl-type phenolic resin structure, active ester compounds containing a triphenol alkane-type phenolic resin structure, active ester compounds containing an aralkyl-type phenolic resin structure with a biphenyl skeleton, active ester compounds containing a biphenyl-type phenolic resin structure, active ester compounds containing an alicyclic phenolic resin structure, active ester compounds containing a heterocyclic phenolic resin structure, active ester compounds containing a phenolic resin structure with a naphthyl ring, active ester compounds containing a resorcinol-type phenolic resin structure, active ester compounds containing an allyl phenolic resin structure, active ester compounds containing a bisphenol A-type resin structure, and active ester compounds containing a bisphenol F-type resin, etc. They can be used alone or in combination of two or more.

[0031] The amount of the epoxy resin curing agent described above is such that, relative to 1 molar equivalent of epoxy groups in component (C), the molar equivalent ratio of functional groups in the epoxy resin curing agent is preferably 0.1 to 4.0, more preferably 0.2 to 2.0. If this molar equivalent ratio is lower than 0.1, unreacted epoxy groups may remain, leading to reduced adhesion; if this molar equivalent ratio is higher than 4.0, the moisture absorption rate of the cured product increases, potentially causing cracking during reflow or temperature cycling. It should be noted that, in this invention, the equivalent refers to the molecular weight of each functional group.

[0032] [(E) Curing Accelerator] The curing accelerator for component (E) can be any curing accelerator that promotes the curing of the above-mentioned (A) bis-citconimide compound and (B) mono-citconimide compound. Commonly known curing accelerators can be used, such as imidazole-based curing accelerators, organophosphorus-based curing accelerators, tertiary amine-based curing accelerators, etc. Among these, from the perspective of suppressing the viscosity of the composition, it is preferable to use an imidazole-based curing accelerator.

[0033] Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, and 2-phenyl-4-methylimidazole. Examples of organophosphorus curing accelerators include phosphine derivatives such as triphenylphosphine, tributylphosphine, tris(p-methylphenyl)phosphine, and tris(nonylphenyl)phosphine; phosphine-borane complexes such as triphenylphosphine-triphenylborane; phosphine borates such as tetraphenylphosphine tetraphenylborate, tetraphenylphosphine tetratolylborate, p-tolyltriphenylphosphine tetratolylborate, and tri-tert-butylphosphine tetraphenylborate; and bis(tetrabutylphosphine)dihydropyromellitic acid tetracarboxylate, etc. Examples of tertiary amine curing accelerators include triethylamine, benzyl dimethylamine, α-methylbenzyl dimethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, and other tertiary amine compounds; 1,8-diazabicyclo[5.4.0]undec-7-ene, etc. Other curing accelerators can also be used in conjunction with these.

[0034] (E) Components can be used alone or in combination of two or more.

[0035] When the total mass of components (A) and (B) is set to 100 parts by mass, the mass of component (E) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 5 parts by mass.

[0036] [Other additives] The thermosetting bis(citronellal)imide resin composition of the present invention may, in addition to components (A) to (E) above, contain other additives as needed, without impairing the purpose or effect of the present invention. Examples of such additives include inorganic fillers, flame retardants, ion traps, antioxidants, adhesives, stress reducers, and colorants.

[0037] Examples of inorganic filler materials include silica-based materials such as fused silica and crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, barium sulfate, talc, clay, aluminum hydroxide, magnesium hydroxide, calcium carbonate, glass fiber, and glass particles. Furthermore, to improve dielectric properties, fluorinated resins, coating fillers, and / or hollow particles can be used; for the purpose of imparting conductivity, conductive filler materials such as metal particles, metal-coated inorganic particles, carbon fibers, and carbon nanotubes can be added. Inorganic filler materials can be used alone or in combination of two or more.

[0038] Flame retardants are added to impart flame retardancy. There are no particular limitations on the type of flame retardant used; all known flame retardants can be used. For example, phosphazene compounds, organosilicon compounds, talc supported on zinc molybdate, zinc oxide supported on zinc molybdate, aluminum hydroxide, magnesium hydroxide, and molybdenum oxide can be used.

[0039] Ion traps are added to capture ionic impurities in the resin composition, thereby preventing thermal and hygroscopic degradation. There are no particular limitations on ion traps; all known ion traps can be used. Examples include hydrotalcites, bismuth hydroxide compounds, and rare earth oxides.

[0040] As antioxidants, there are no particular limitations, and examples include, for instance, n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acetate, neo-dodecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, dodecyl-2-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, ethyl-1-(4-hydroxy-3,5-di-tert-butylphenyl)isobutyrate, octadecyl-1-(4-hydroxy-3,5-di-tert-butylphenyl)isobutyrate, and octadecyl-1-(4-hydroxy-3,5-di-tert-butylphenyl)isobutyrate. 2-(n-octylthio)ethyl-3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2-(n-octylthio)ethyl-3,5-di-tert-butyl-4-hydroxyphenylacetate, 2-(n-octadecylthio)ethyl-3,5-di-tert-butyl-4-hydroxyphenylacetate, 2-(n-octadecylthio)ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2-(2-stearoyloxyethylthio)ethyl-7-(3-methyl-5-tert-butyl-4-hydroxyphenyl)heptanoate, 2-hydroxyethyl-7-(3-methyl-5-tert-butyl-4-hydroxyphenyl)propionate and pentaerythritol tetra[ Phenolic antioxidants such as 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearate-3,3'-thiodipropionate, ditridecyl-3,3'-thiodipropionate, and pentaerythritol tetra(3-lauryl thiopropionate); tridecyl phosphite, triphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, 2-ethylhexyl diphenyl phosphite, diphenyltridecyl phosphite, and 2,2-methylenebis(4,6-di-tert-butyl) phosphite. Phosphorus-based antioxidants include octyl 2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and 2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepine-6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepine-6-yl]oxy]-ethyl]ethylamine.

[0041] The amount of other additives varies depending on the purpose of the composition, and is less than 10% by mass of the total composition.

[0042] [Method for manufacturing the composition] The thermosetting bis(citroxy)imide resin composition of the present invention can be manufactured by the method described below. For example, as needed, components (A) to (E) can be heated simultaneously or separately while being mixed and stirred to dissolve and / or disperse them, thereby obtaining a mixture of components (A) to (E). Preferably, the mixture of components (A) to (E) can be obtained by adding epoxy resin curing agent (D) to the mixture of components (A), (B), (C), and (E) and stirring to dissolve and / or disperse them. More preferably, the mixture of components (A) to (E) can be obtained by adding epoxy resin curing agent (D) to the mixture of components (A), (B), (C), and (E) while heating component (B) above its melting point and stirring to dissolve and / or disperse it. In addition, depending on the application, at least one of flame retardant, polymerization initiator, and ion trapping agent can be added to the mixture of components (A) to (E) and mixed. Each component can be used alone or in combination of two or more.

[0043] In the method of manufacturing the composition, there are no particular limitations on the apparatus used for mixing, stirring, and dispersing. Specifically, for example, a pounder, two-roll mill, three-roll mill, ball mill, planetary mixer, or mass colloider with stirring and heating devices can be used, or these devices can be used in appropriate combinations.

[0044] The curing and molding method, curing and molding conditions of the thermosetting bis(citronellal)imide resin composition of the present invention can be known methods and conditions. Preferably, initial curing is performed in a hot oven at 100–120°C for 0.5 hours or more, followed by hot oven curing at 150–175°C for 2 hours or more. Heating at 100–120°C for 0.5 hours or more can suppress voids that may form after curing. Furthermore, heating at 150–175°C for 2 hours or more yields sufficient cured product properties. [Example]

[0045] The present invention will be described in more detail below with examples and comparative examples, but the present invention is not limited to the following examples. It should be noted that in Table 1, the amount of each component is expressed as parts by mass.

[0046] The components used in the examples and comparative examples are represented below. It should be noted that the number-average molecular weight (Mn) below is determined under the conditions described below. 1 The number-average molecular weight calculated from the H-NMR determination results. [Measurement Conditions] Device: AVANCE III400 manufactured by Burker Solvent: CDCl3 Internal standard: Tetramethylsilane (TMS)

[0047] The viscosities of components (A) and (B) are those measured using an E-type viscometer (BROOKFIELD DV-III ULTRA). Approximately 1.0 mL of sample was placed into the measuring cup provided with the E-type viscometer. This measuring cup was placed in a thermostatic bath / liquid supply device (KISS-K6, manufactured by Eiko Seiki Co., Ltd., Japan) with the temperature set at 25°C. The rotational viscosity of the sample was measured using the E-type viscometer, and the value of the rotational viscosity at the point where the rotational viscosity indicator value stabilized was recorded. (B) The melting point of the component is the melting point determined using a differential scanning calorimeter (DSC3+ manufactured by METTLER TOLEDO).

[0048] (A) Bisciconiamide compound Synthesis Example 1 (Preparation of the bis-citronellimide compound) 71.2 g (0.45 mol) of 2,2,4-trimethylhexamethylenediamine, 111.0 g (0.99 mol) of citrate anhydride, and 150 g of toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize the amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. While stirring for 16 hours to remove by-product water by distillation, the reaction solution was washed five times with 200 g of deionized water. Then, 149.7 g (96% yield) of the target compound ((A1), number-average molecular weight 590, viscosity 20 Pa·s at 25 °C) was obtained at room temperature (25 °C) by vacuum stripping at 60 °C. 1 H-NMR analysis confirmed that the target compound was a citrile imide compound represented by the following formula (A1). [Chemical Formula 10]

[0049] (A2) Bisciconiamide compound The bisciconimide compound represented by the following formula (trade name: BCI-1500, manufactured by Designer Molecules Inc.) (liquid at 25°C, number-average molecular weight of 2300, valence of ciconimide group = 0.095 mol / 100g) [Chemical Formula 11] -C 36 H 70 - indicates a structure derived from a dimer acid backbone. m≈2 (average value)

[0050] (B) Monociconiamide compounds Synthesis Example 2 (Preparation of monociconimidin compounds) 81.0 g (0.80 mol) hexylamine, 98.6 g (0.88 mol) citrate anhydride, and 150 g toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. While stirring for 16 hours to remove by-product water by distillation, the reaction solution was washed five times with 200 g of deionized water. Then, 110.9 g (71% yield) of the target compound ((B1), viscosity 9 mPa·s at 25 °C) was obtained at room temperature (25 °C) by vacuum stripping at 60 °C. 1 H-NMR analysis confirmed that the target compound was a monociconimidin compound represented by the following formula (B1). [Chemical Formula 12]

[0051] Synthesis Example 3 (Preparation of monociconimidin compounds) 96.9 g (0.80 mol) of 1-phenylethylamine, 98.6 g (0.88 mol) of citralic anhydride, and 150 g of toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize the amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. While stirring for 16 hours to remove by-product water by distillation, the reaction solution was washed five times with 200 g of deionized water. Then, 141.2 g (82% yield) of the target compound ((B2), viscosity 92 mPa·s at 25 °C) was obtained at room temperature (25 °C) by vacuum stripping at 60 °C. 1 H-NMR analysis confirmed that the target compound was a monociconimidin compound represented by the following formula (B2). [Chemical Formula 13]

[0052] Synthesis Example 4 (Preparation of monociconimidin compounds) 96.9 g (0.80 mol) of 2-phenylethylamine, 98.6 g (0.88 mol) of citralic anhydride, and 150 g of toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize the amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. The solution was stirred for 16 hours while distilling off the byproduct water. The reaction solution was then washed five times with 200 g of deionized water. Finally, 142.9 g (83% yield) of the target compound ((B3), melting point 52 °C) was obtained at room temperature (25 °C) by vacuum stripping at 60 °C. 1 H-NMR analysis confirmed that the target compound was a monociconimidin compound represented by the following formula (B3). [Chemical Formula 14]

[0053] Synthesis Example 5 (Preparation of monociconimidin compounds) 119.4 g (0.80 mol) of 3-amino-1-phenylbutane, 98.6 g (0.88 mol) of citralic anhydride, and 150 g of toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize the amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. While stirring for 16 hours to remove by-product water by distillation, the reaction solution was washed five times with 200 g of deionized water. Then, 134.3 g (69% yield) of the target compound ((B4), viscosity 141 mPa·s at 25 °C) was obtained by vacuum stripping at 60 °C at room temperature (25 °C). 1 H-NMR analysis confirmed that the target compound was a monociconimidin compound represented by the following formula (B4). [Chemical Formula 15]

[0054] Synthesis Example 6 (Preparation of monociconimidin compounds) 90.6 g (0.80 mol) of cyclohexanemethylamine, 98.6 g (0.88 mol) of citralic anhydride, and 150 g of toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize the amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. The solution was stirred for 16 hours while distilling off the byproduct water. The reaction solution was then washed five times with 200 g of deionized water. Finally, 137.6 g (83% yield) of the target compound ((B5), melting point 47 °C) was obtained at room temperature (25 °C) by vacuum stripping at 60 °C. 1 H-NMR analysis confirmed that the target compound was a monociconimidin compound represented by the following formula (B5). [Chemical Formula 16]

[0055] Synthesis Example 7 (Preparation of monociconimidin compounds) 137.0 g (0.80 mol) of 1-(1-naphthyl)ethylamine, 98.6 g (0.88 mol) of citralic anhydride, and 150 g of toluene were added to a 2 L four-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer to prepare a reaction solution. The solution was stirred at 80 °C for 3 hours to synthesize the amyl acid. Then, 40 g of methanesulfonic acid was added to the reaction solution, and the mixture was heated to 110 °C. The solution was stirred for 16 hours while distilling off the byproduct water. The reaction solution was then washed five times with 200 g of deionized water. Finally, 176.2 g (83% yield) of the target compound ((B6), melting point 88 °C) was obtained at room temperature (25 °C) by vacuum stripping at 60 °C. 1 H-NMR analysis confirmed that the target compound was a monociconidium imide compound represented by the following formula (B6). [Chemical Formula 17]

[0056] (C) Epoxy resin (C1) Bisphenol A type epoxy resin (jER828EL: manufactured by Mitsubishi Chemical Corporation, Japan, liquid at 25°C, epoxy equivalent of 189)

[0057] (D) Epoxy resin curing agent (D1) Phenolic varnish type allyl phenolic resin (MEH-8000H: manufactured by Meiwa Kasei Corporation, Japan, phenolic hydroxyl equivalent is 141)

[0058] (E) Curing accelerator (E1)2-Ethyl-4-methylimidazolium (2E4MZ: Manufactured by Shikoku Chemical Industry Co., Ltd., Japan)

[0059] The above components were mixed in the proportions (parts by mass) listed in Table 1 to obtain the compositions. The penetration, relative permittivity, dielectric loss tangent, and adhesion of each composition and its cured product were evaluated using the methods shown below. The results are presented in Table 1. It should be noted that the "equivalent ratio" listed in Table 1 refers to the ratio of the molar equivalent (active hydrogen equivalent) of the functional groups of the epoxy resin curing agent in component (D) to the molar equivalent of one epoxy group contained in the epoxy resin in component (C).

[0060] 1. Viscosity at 25℃ The viscosity of each thermosetting resin composition of the examples and comparative examples was measured at 25°C using an E-type viscometer (DV-III ULTRA manufactured by BROOKFIELD). Approximately 1.0 mL of sample was placed in a measuring cup attached to the E-type viscometer, which was then placed in a thermostatic bath / liquid supply device (KISS-K6 manufactured by Eiko Seiki Co., Ltd., Japan) with the temperature set at 25°C. The rotational viscosity of the sample was then measured using the E-type viscometer, and the value of the rotational viscosity at the point where the indicated value of the rotational viscosity stabilized was read.

[0061] 2. Relative permittivity and dielectric loss tangent A mold frame with a thickness of 30mm × 40mm × 100μm was prepared. The thermosetting resin compositions of the examples and comparative examples were clamped in a 50μm thick PET film (E7006, manufactured by Toyobo, Japan) after demolding treatment. The mixture was then molded using a vacuum press (manufactured by NIKKO-MATERIALS CO.,LTD) at 180°C for 5 minutes to obtain a cured product. The cured product was removed from the PET film and further primary cured at 165°C for 3 hours to obtain a cured resin film. Using the cured resin film, a network analyzer (manufactured by Keysight Technologies, Inc., E5063-2D5) was connected to a stripline (manufactured by Keycom Co., Ltd.), and the relative permittivity and dielectric loss tangent of the cured resin film at a frequency of 10 GHz were measured.

[0062] 3. Determination of Tg Using a mold frame with a thickness of 5mm × 5mm × 15mm, the thermosetting resin compositions of the examples and comparative examples were molded and cured at 165°C for 3 hours to obtain test pieces. These test pieces were placed in a thermal expansion tester (TMA8140C manufactured by Rigaku Corporation). The heating program was then set to a heating rate of 10°C / min, with a constant load of 19.6mN applied, and the dimensional changes of the test pieces from 25°C to 260°C were measured. The relationship between this dimensional change and temperature was plotted in a graph. In the graph of dimensional change versus temperature obtained in this way, the intersection of the tangent line of the dimensional change-temperature curve below the inflection point temperature and the tangent line of the dimensional change-temperature curve above the inflection point temperature is taken as the glass transition temperature (Tg).

[0063] Table 1

[0064] The results in Table 1 demonstrate that by using monociconimide compounds and bisciconimide compounds with melting points below 60°C, the viscosity of the thermosetting bisciconimide resin composition of the present invention is reduced, and the cured product exhibits excellent dielectric properties (low relative permittivity and low dielectric loss tangent).

Claims

1. A thermosetting biscitraconimide resin composition comprising: (A) a biscitraconimide compound represented by the following formula (1), [Chemical Formula 1] ###0001### in the formula (1), B is a divalent organic group, (B) a monocitraconimide compound represented by the following formula (2) having a melting point of 60°C or lower, [Chemical Formula 2] ###0002### in the formula (2), A is a group selected from the hydrocarbon groups represented by the following structures, [Chemical Formula 3] ###0003### R is independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, Q is a linear or branched alkylene group having 1 to 10 carbon atoms, and * indicates bonding to a nitrogen atom in a citraconimide group, (C) an epoxy resin, (D) an epoxy resin curing agent, and (E) a curing accelerator.

2. The thermosetting biscitraconimide resin composition according to claim 1, wherein, in the formula (1), B is at least one group selected from the groups represented by the following structures and a hydrocarbon group from a dimer acid skeleton, [Chemical Formula 4] ###0004### * indicates bonding to a nitrogen atom in a citraconimide group, and n is 1 to 20.

3. The thermosetting biscitraconimide resin composition according to claim 1, wherein, the biscitraconimide compound of (A) has a melting point of 25°C or lower.

4. The thermosetting biscitraconimide resin composition according to claim 1, wherein, the biscitraconimide compound of (A) has a number average molecular weight of 200 to 10,000.

5. The thermosetting biscitraconimide resin composition according to claim 1, wherein, the epoxy resin of (C) is an epoxy resin having two or more epoxy groups in one molecule.

6. The thermosetting biscitraconimide resin composition according to claim 1, wherein, the epoxy resin curing agent of (D) is one or more selected from the group consisting of an amine compound, a phenol compound, an acid anhydride compound, and an active ester compound.

7. The thermosetting biscitraconimide resin composition according to claim 1, wherein, the curing accelerator of (E) is one or more selected from the group consisting of an imidazole-based curing accelerator, an organic phosphorus-based curing accelerator, and a tertiary amine-based curing accelerator.

8. The thermosetting biscitraconimide resin composition according to claim 1, wherein, with respect to 100 parts by mass of the total of the (A) component and the (B) component, the (B) component is 1 to 30 parts by mass, the (C) component is 1 to 100 parts by mass, with respect to 1 mole equivalent of the epoxy groups in the (C) component, the mole equivalent ratio of the functional groups that react with the epoxy groups in the (D) component is 0.1 to 4.0, and the (E) component is 0.01 to 20 parts by mass. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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